Ledger Nano S or wait for Trezor 2 which will be released soon. I would stay away from Keepkey they bought Multibit wallet and after sometime they quit development for it, not the kind of persons I would rely on to buy a hardware wallet. Ledger Nano S has the best price and it supports multi currency, it supports Bitcoin, Ethereum and Litecoin if I remember correctly so it is the best bang for the buck.

There may be other options outside these but these seem to be the industry leaders and to keep your $ safe you want to remain with the best of the best. That being said I personally have used and loved using a Trezor, but

I have seen videos for the others and they also seem capable and as durable as the Trezor. Dont think you can go wrong between those 3 tbh although I think Trezor and Ledger are a bit better options.

Trezor was the original hardware wallet and a Trezor bought in 2014 still works fine today. I own one of them. Ledger Nano S is the competition. Contrast this to the Case hardware wallet which came out to great fanfare but no longer works because the fees used are too low and cannot be updated.

Case is now obsolete and anyone who spent $199 for it has a paperweight. KeepKey took Trezor code and forked it when they came out with their hardware wallet. It is very pretty but I worry if they are in it for the long haul.

I would stick with Trezor or Nano S. Most of us own both of them because some altcoins might only be available on one or the other. Also the user experience is different. You might prefer the Nano S GUI while I like Trezor. Both are top shelf. Nano S does have a longer warranty, two years where Trezor is one year.

Trezor T will ship in January and uses a new operating system which is supposed to make it easy for developers to add new coins. The original Trezor will still work fine and be updated but there is the possibility some new coins might only be available on Trezor T which has more memory.

Don't wait for Trezor T if you do not own a hardware wallet right now. Go ahead and get either a Trezor or Nano S so you can protect your private keys.

There may be other options outside these but these seem to be the industry leaders and to keep your $ safe you want to remain with the best of the best. That being said I personally have used and loved using a Trezor, but

I have seen videos for the others and they also seem capable and as durable as the Trezor. Dont think you can go wrong between those 3 tbh although I think Trezor and Ledger are a bit better options.

There's minor difference between Trezor (original) and Nano S, both have screen, which is a minimum requirement for security. The altcoin support is the difference, the Nano S supports a bit more alt than the Trezor but both are working on the support of various alts . Maybe you can hang the Nano S on a keychain, because of it's shape but that's only a personal preference.

I perosnally use Ledger Nano S. I would certainly recommend it because its quite affordable than rest of the options and provide you with a quite high level of security. Also it can even store a few altcoins which makes it even better to use.